This invention relates to a universal serial bus (USB) connector comprising a special USB plug and a USB receptacle selectively mateable with at least two types of USB plugs including the special USB plug. The USB receptacle according to this invention has a detecting structure for identifying the type of the USB plug mated therewith.
Recently, a USB receptacle connectable to a standard USB plug (i.e. a USB plug) compliant with a USB standard is required to be also connectable to a special USB plug (i.e. another USB plug) configured by modifying the standard USB plug. Moreover, the USB receptacle connected to the special USB plug is required to work differently from the USB receptacle connected to the standard USB plug.
For example, when the USB receptacle supplies a bus-power to a device connected with the USB receptacle via the USB plug, it is preferred to supply different power according to the type of the connected device. More specifically, if the USB receptacle is connected with a device operable with a small power, it is necessary to supply such a small power that the device is not damaged. On the contrary, if the USB receptacle is connected with a device (for example, an external hard disk drive) which needs a large power, it is necessary to supply the large power. In other words, the USB receptacle is required to supply a proper power according to the connected device. If the USB receptacle is able to identify the mated USB plug, the proper power may be supplied by connecting the device via different USB plug according to the power to be supplied.
For example, a USB receptacle and a USB plug mateable with each other are disclosed in JP-A 2005-242476 (Patent Document 1), JP-U 3172188 (Patent Document 2) and JP-A 2003-197302 (Patent Document 3), contents of which are incorporated herein by reference.
Each of the USB receptacles disclosed in Patent Document 1 and Patent Document 2 is provided with a detecting structure for detecting whether the USB plug is connected or not. Each of the USB receptacle and the USB plug disclosed in Patent Document 3 has an additional power contact in addition to contacts (for example, signal contacts) compliant with the USB standard. The additional power contact is used for electric power transmission to a hard disk drive, etc.
However, the aforementioned detecting structure is configured without considering a case where a plurality of types of the USB plugs are selectively mateable. More specifically, the aforementioned USB receptacle with the detecting structure is not configured to identify the type of the mated USB plug. Moreover, the USB receptacle with the detecting structure has no additional power contact.
According to Patent Document 3, the power contact (i.e. the additional power contact) of the USB receptacle is brought into contact with an edge (i.e. a side edge) of a power contact of the USB plug. Accordingly, a contact area between the power contacts is smaller than a contact area between the signal contacts. In other words, the contact area between the power contacts is very small so that it is difficult to transmit the power properly.
As can be seen from the above description, it is required a technique to identify the type of the mated USB plug. Moreover, it is required a more practical technique to properly supply the power to the connected device.